Brilliant! Thank you.

Debug shows Payment Failed and whole load of other data but the important bit is...

            [L_ERRORCODE0] => 10002
            [L_SHORTMESSAGE0] => Restricted account
            [L_LONGMESSAGE0] => Account is restricted
            [L_SEVERITYCODE0] => Error

... i think.

I'll have to figure out why this is coming back as restricted.

Thanks again.